engleski

Spatial and temporal trends in heavy metal accumulation in mosses in Europe (1990-2005)

The heavy metals in mosses biomonitoring network was originally established as a Swedish initiative (Rühling and Skärby, 1979). The idea of using mosses to measure atmospheric heavy metal deposition is based on the fact that carpet forming, ectohydric mosses obtain most trace elements and nutrients directly from precipitation and dry deposition ; there is little uptake of metals from the substrate (Tyler, 1970). The technique of moss analysis provides a surrogate, time-integrated measure of metal deposition from the atmosphere to terrestrial systems. It is easier and cheaper than conventional precipitation analysis as it avoids the need for deploying large numbers of precipitation collectors with an associated long-term programme of routine sample collection and analysis. Therefore, a much higher sampling density can be achieved than with conventional precipitation analysis. Heavy metals deposited from the atmosphere tend to be retained by the mosses, thereby making sampling and chemical analysis more robust and less prone to contamination. Heavy metal data from precipitation analysis can be very uncertain if the detection limit of the applied analytical techniques is high (Ilyin et al., 2006). Despite improvement of the analytical techniques, the latter remains a problem due to the general decline in anthropogenic emissions and subsequent deposition of heavy metals in recent decades. Although the heavy metal concentration in mosses provides no direct quantitative measurement of deposition, this information can be derived by using regression approaches relating moss and precipitation monitoring data (e.g. Berg and Steinnes, 1997 ; Berg et al., 2003). A more detailed review of the moss technique and its applications has been provided by Onianwa (2001), Tyler (1990) and Zechmeister et al. (2003). During 2001, responsibility for the coordination of the European moss survey was handed over from the Nordic Working Group on Monitoring and Data, Nordic Council of Ministers, to the UNECE ICP Vegetation Programme Coordination Centre at the Centre for Ecology and Hydrology (CEH) Bangor, UK. The ICP Vegetation was established in the late 1980s to consider the science of the effects of air pollution on vegetation. It is one of seven ICPs/Task Forces that report to the Working Group on Effects (WGE) of the Convention on Long-range Transboundary Air Pollution (LRTAP). The WGE monitors and reviews the effects of atmospheric pollutants on different components of the environment (e.g. forests, fresh waters, vegetation, buildings) and human health (Working Group on Effects, 2004).

heavy metals; mosses biomonitoring; atmospheric heavy metal deposition

CEH Programmes up to 2009 > Biogeochemistry > BG01 Measuring and modelling trace gas, aerosol and carbon > BG01.4 Metals